I haven't replaced mine,but the problems I'm having go away once the ESC 4-wire harness at the HEI dist. or the ECM is disconnected.

I'm not a master technition,...but I'd say the computer is bad.

 

I'm sorry,forgot to mention,this was my '84 T/A w/305 HO (L69) engine (vin code G)

 

_I_ never replaced mine, but my friend did in his 91 Camaro RS 3.1 auto. How did he determine it faulty? haha, funny story, his fan wouldn't turn on. _COULD NOT_ figure out why... bypassed relays checked motors, checked sensors, grounds, wires, everything... Eventually they dialed it in on a scanner and saw that the ECM was reading the temp backwards (-220 degrees)... so he changed it...

At this point he could have stopped, but read on, it gets better...

After this, it still didn't work... car still heated up... WHY!?

Simple, when he put the ECM in he blew the fuse for the fan, hatch release and dome light... when we noticed these things we just said, "oh no, not more crap breaking"... took another day to realize he blew the fuse....

Put a new fuse in, everything works great! Fan works... everything.

That is my ECM related story. "He replaced his ECM, and -that- is why."

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1985 Camaro SC - 2.8L, auto.

Mods:
Removed air baffles, mandrel bent cat-back pipes (but stock replacment muffler, Dynomax Turbo and Catco converter are on thier way)

 

Mine was there, That's how I determined it was faulty.

 

In the borg warner reman computers there's a sheet inside the box that lists three different ways to check all the sensors, the old computer (for burnt drivers) using a resistance meathod and a voltage drop test. They won't warranty the new computer unless you make sure the sensors are not bad causing the drivers to burn up, and once you break the shrink wrap on the computer, it's yours, no returns...

 

I had to replace a computer in my 87 Grand Am. When I bought the car, the guy gave me a thick azs repair manual he ordered when he bought the car new. This manual had simple flow charts for checking all the sensors and determining if a sensor or the computer was bad. So I followed the chart, replaced the computer and car was fine!

I still have the manual, since most GM cars are almost electrically the same.

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86 Sport Coupe, 2.8 V6, dead stock, but not for long!

Daily driver:
2000 Pontiac Grand Am SE2

"Little girls play with ponies!"
www.geocities.com/camman86

[This message has been edited by Mikes86SC (edited June 13, 2001).]

 

In my instance, the electric fan wuld not shut off.
I played with relays (wasted money as I strongly suspected they were fine) and other stuff.
I got a ECM, disconnected the battery, unplugged unit, took out prom, insterted prom in other ecm, hooked up ecm, connected battery, started up car. It worked perfect.
My ECM came from a V-8 car, for my V-6. Swapped proms, was the trick.
I feel real lucky. TRY TO FIND OUT (thru the wrecking yard swap manual) what ECM works for your application then go get it.

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Chat Soon,
KED85
Karl
1985 Firebird 2.8 to 3.4 swap project for Smog Happy LA, CA

 

I thought that the computer itself could tell you if it was bad or not. I thought the computer would send a trouble code if it was bad.

 

I replaced mine after the tranny shop said they weren't getting any data stream on their diagnostic when they were trying to get my lockup working. I had a steady check engine light, and it wouldn't give me that one flash when the ignition was turned to 'run'.
In my case, though, my car had been de-computerized by the previous owner, and the connectors on the harness chopped off with the wires left dangling on the engine. Yeah, it was more or less a partially-educated guess, but everything started working once I installed the new ECM after I had put everything back together, and I still have the factory PROM in there. (sure was nice to see that Check Engine light extinguish!)

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DR Stevens
1984 Trans Am 305HO L69
1991 Firebird 305 L03

 

I would strongly caution you to check everything before you do this. I have been fooled and conned into buying two ECMs in my life and neither time was the fault with the ECM.


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Rob P
89RSconvtZZ4TPI
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